The art of printing images with micro-fluid technology is relatively well known. A permanent or semi-permanent ejection head has access to a local or remote supply of fluid. The fluid ejects from an ejection zone to a print media in a pattern of pixels corresponding to images being printed. Over time, the fluid drops ejected from heads have become increasingly smaller to increase print resolution. Multiple ejection chips joined together are also known to make lengthy arrays, such as in page-wide printheads.
Fluid ejections near boundaries of adjacent chips have been known to cause problems of image “stitching.” Registration needs to occur between fluid drops from adjacent firing elements, but getting them stitched together is difficult when firing elements reside on different substrates. Also, challenges to stitching increase as arrays grow into page-wide dimensions, or larger. While some designs have layouts intending to accommodate stitching, they have been observed to complicate chip fabrication. They introduce firing elements near terminal ends of chips to align lengthwise with colors shifted laterally by one fluid via on same or adjacent chips. They also reside on complexly shaped substrates.
In other designs, narrow print zones tend to favor narrow ejection chips. On opposing chips, adjacent fluid vias having a same fluid color demand exceptionally short distances in page-wide arrays to achieve high quality imaging. Simply moving adjacent chips closer to one another to narrow the print zone has inherent limitations in how closely the chips can be aligned. If chips are singulated from wafers by dicing, scribe lines introduce dicing streets widths of several tens of microns. Dicing along the streets leaves imperfect edges that prohibit fitting chips next to one another any closer than the several tens of microns dictated during scribing. While results vary from one technique to the next, none provide relief in making distances measurably shorter. Dicing also subjects the chips to considerable chipping and cracking damage along its sidewalls, especially in corner regions. The damage can cause elevated failure rates during later handling and subsequent assembly.
A need exists to significantly improve conventional ejection chip designs for larger stitched arrays. The need extends not only to improving stitching, but to manufacturing, handling and subsequent assembly. Additional benefits and alternatives are also sought when devising solutions.